$sitelib should be $prefix/lib/perl5/site_perl, as documented in

INSTALL (from Andy Dougherty)

p4raw-id: //depot/perl@4713

diff --git a/Configure b/Configure
index 2f74812..411982b 100755 (executable)
--- a/Configure
+++ b/Configure
@@ -6778,7 +6778,7 @@ siteprefixexp="$ansexp"
 : XXX No longer works with Prefixit stuff.
 prog=`echo $package | $sed 's/-*[0-9.]*$//'`
 case "$installstyle" in
-*lib/perl5*) dflt=$siteprefix/lib/site_$prog ;;
+*lib/perl5*) dflt=$siteprefix/lib/$package/site_$prog ;;
 *)      dflt=$siteprefix/lib/site_$prog ;;
 esac
 $cat <<EOM